Copper Phosphide

Jewelry Discussion
1

I have heard that Copper Phosphide added to silver alloys can enhance
the grain structure and working characteristic. Does anyone have any
experience or Knowledge of this practice? David Mcleod

Anne Jackman & David McLeod
Granton Studios
Harington Point Road
2 RD
Dunedin
New Zealand
ph:     0064  3  4780 635
email:  @Anne_Jackman_David_M
2

The references to “phos-copper” that I’ve seen, and as I’ve used it,
were to control excess oxidation of the silver. It’s a powerful
deoxidizer used just before casting. I used it when making ingots
that needed to roll out into decent metal, from scrap sterling.
Without it, I was getting too many bubbles in the metal when I’d go
to anneal it after the first few passes through the rolls. With it,
the bubbles were greatly reduced. I don’t know about grain structure
changes with this, but certainly the reduction in gas pockets and
oxide pockets causing defects in rolled or drawn metal was certainly
a boon.

Peter Rowe

3

Are you using the phos copper shot used in the bronze foundries or
are you using pieces of sil phos copper brazing alloy? Jesse

4

Hi Peter,

This sounds like something worth having around the shop!

Can you give us a source for the ‘phos-copper’ additive? If you have
the address for anyone supplying a ‘User’s Guide’ or other info that
would sure be appreciated as well.

Thanks again for taping your vast well of knowledge for the the
common good.

Dave

5 
Can you give us a source for the 'phos-copper' additive? If you have
the address for anyone supplying a 'User's Guide' or other info that
would sure be appreciated as well.

David, according to Working in Precious Metals by Ernest A Smith,
“This use of phosphorous as a deoxidiser for gold alloys may be
regarded as the scientific method of applying the old smelters’
secret remedy for refracrory gold by adding phosphourus match heads,
and red tips were always specified, when melting his gold to bring it
to “nature.” Phosphor-copper may also be applied satisfactorly for
the deoxidation of silver alloys.”

He also recommends that the content of the phosphor not exceed .05%.
But that in some cases it works in as little as .01% or even as high
as .1%. Let us know how it works for you. Peter Slone

6 
  Can you give us a source for the 'phos-copper' additive? If you
have the address for anyone supplying a 'User's Guide' or other info
that would sure be appreciated as well.

Can’t help ya on this. I’ve got a little jar of pellets of the stuff
that I got over 20 years ago. Use it infrequently enough that it will
last a while longer too. I’d suggest the Thomas Register, or foundry
supplies. The stuff was intended as a casting additive in foundary
work. I found the original reference to it, if I recall right, in a
book which is a translation from one originally published in german.
Not going to go downstairs to check the exact title, but as I recall,
it was by Wilhelm Braun-Feldwig, titled Metalwork, or some such. Was
only a very brief reference anyway, so not of much additional use.
At the time, I was a student at Cranbrook (this is the late 70’s mind
you), and as it happened, Richard Thomas, the instructor there at the
time, had a bunch of the stuff, and gave me some. That’s about all I
know at the moment. But it shouldn’t be too hard to track down if you
talk to the foundry folks…

Peter Rowe

7 
    This sounds like something worth having around the shop! Can
you give us a source for the 'phos-copper' additive?

I use this as well in any alloys with a copper content as a
de-oxidiser. It’s the copper component that can be a propblem, as it
absorbs gasses during the melr and hangs onto them.

I call it Copper-Phos, and I get it from a local foundry here. I
first learned of its use from Phil Baldwin, who does all the bi-metals
and shakudo and shibuichi alloys on sale at Reactive Metals
<www.reactivemetals.com>.

Cu-Phos now comes in handy tiny pellets like tiny shot. I use about
0.5% added to the melt 20 - 30 seconds before pouring.

As it’s a great de-oxidieser I use a flame (oxy-propane) that is
deliberately more oxidising than normal. This heats the charge up
quicker, and after all I’m ‘de-oxidising’ aren’t I. The extra oxigen
prevents excess hydrogen in the flame (one won’t exist if the other is
there) and thence being absorbed in the metal, combining with ox in
the atmosphere and turning into H2O (steam) and causing blow-outs. To
quote someone before me (Gareth White) ‘The optimum amount of
phosphorous to use in casting is simple “just enough”.’

I don’t know of a supplier in your country.

Regards

bri

B r i a n A d a m J e w e l l e r y E y e w e a r
@Brian_Adam1 ph/fx +64 9 817 6816 NEW ZEALAND
http://www.adam.co.nz/ photos from Australia!!
http://www.adam.co.nz/jam.htm Jewellery Events on now

8

I looked in my area (Tempe Arizona) for Copper Phosphide after Brian
left after doing a WONDERFUL Spectacles Workshop. The foundry that I
went to had NO idea what I was talking about. If anyone finds a
source, I would be interested in getting some.

Thanks
Joan

9 
    I looked in my area (Tempe Arizona) for Copper Phosphide after
Brian left after doing a WONDERFUL Spectacles Workshop.  The foundry
that I went to had NO idea what I was talking about. If anyone finds
a source, I would be interested in getting some.

Cheers Joan. I’ve emailed Reactive Metals, asking if they can help
with a supplier. Anyone else wants it and you happen to be passing
through Auckland:

Hayes Metal Refining
Osborne Street
Newmarket
Auckland
New Zealand
ph +64 9 520 2059

Bri

B r i a n A d a m J e w e l l e r y E y e w e a r
@Brian_Adam1 ph/fx +64 9 817 6816 NEW ZEALAND
http://www.adam.co.nz/ photos from Australia!!
http://www.adam.co.nz/jam.htm Jewellery Events on now

10

I am not sure that they would carry it but so far Bryant Labs in
Berkeley, CA. has not failed me in searches for any compounds. And
if they don’t have it, I bet they will know how to find a source!
Shael

11

For silver there are common brazing alloys that are basicly copper
with a small percentage of silver 5-15% silver plus some phosporus .
These are called silphos. They will be available at welding supply
distributors everywhere, They are supplied as brazing filler rod in
sticks about 1/16 --1/8" dia sometimessort of flat. Pick up
from one of these distributors. Metal alloy content should
be found on sites for Eutectic, Handy and Harmon, Harris etc. These
will be very convenient to use in making up casting alloys from fine
silver since the rod contents are well known and its easy to clip off
the weight of material you need. These rods are used as a self fluxing
brazing alloy for copper. I get some of the phos -copper from a local
foundry that we tried in casting bronze sculpture. This is only copper
with some phosporus . It didn’t melt in well and inspite of stiring a
50 pound melt I have a sculpture that seems to have an disolved lump
in it, only 2-3 pieces of shot were added. if you are working silver
the brazing rod is a real good way to go. if you need more help- ask
Jesse